The present invention relates to concrete forms (i.e., to forms which can be used for the pouring and setting of concrete walls, roofs, ceilings, floors or the like), and more particularly to improvement in the construction and design as well as in the method of assembling and especially in the method of dismantling such forms. Still more particularly, the invention relates to improvements in concrete forms which are or can be utilized with advantage to support the undersides of horizontal or substantially horizontal concrete walls, floors or roofs and embody several panels or boards having surfaces which contact the underside of a concrete wall or the like.
It is known to assemble a concrete form which is used to support a concrete roof from below by resorting to several panels which are connected to each other so as to provide a relatively large plate-like body capable of supporting the plasticized material during pouring as well as during hardening or setting. Once the material sets, the form must be removed for storage or for transfer to another locale of use. As a rule, the panels are mounted on top of props or studs which ensure that the upper sides of the panels are located at the optimum level, namely, at the level of the underside of the roof to be made of concrete or an analogous plasticizable and hardenable material (for the sake of convenience, the invention will be described with reference to the pouring and hardening of concrete walls or the like, it being understood, however, that the same or a similar form can be resorted to for the making of walls, roofs or floors which consist of a plasticizable building material other than concrete). The installation of panels in the area below the concrete roof of a building or another edifice presents fewer problems than the dismantling and removal of the form. Thus, and if the side walls of a structure are readily completed, the form is installed between such side walls and the upper sides of the panels are held at the requisite level prior to pouring of concrete on top of the form. When the concrete hardens, the form must be dismantled in the space below the thus obtained roof, and this can present many problems as regards the removal of props and subsequent detachment of panels from each other preparatory to removal of detached panels from the space below the roof.
In accordance with the presently known proposal, the panels of a concrete form consist of wood and have smooth first sides which face the space for the pouring of concrete as well as second sides which carry reinforcing ribs. The ribs are normally disposed along the marginal portions of the panels. The panels are mounted in specially designed supports or holders which ensure that the smooth first sides of neighboring panels are at least substantially coplanar during pouring and setting of concrete. The holders are provided at the upper ends of props which carry the panels during the pouring of a horizontal concrete ceiling, roof or the like. As a rule, such holders are adjustably mounted on the props or on the heads of the props so that they can be lowered with or detached from the heads prior to removal of panels after hardening of concrete.
It is also known to provide the heads of props with intersecting grooves for reception of adjacent portions of reinforcing ribs at the underside (second sides) of the panels thereabove. The heads preferably diverge upwardly toward the undersides of the panels so as to provide relatively long grooves for and, hence, a better guidance and support of the ribs. Each head can comprise a base plate and an upwardly diverging portion with the aforementioned grooves. The heads are designed in such a way that they can receive portions of ribs on two neighboring panels or portions of ribs at the junction of corners of four neighboring panels. To this end, the grooves of a head may constitute, in their entirety, a composite groove of cruciform shape.
The just discussed conventional forms exhibit a number of serious drawbacks. Thus, each panel must be placed, individually, on top of the corresponding props so that the assembly of the form consumes a substantial amount of time. The situation is aggravated during dismantling of the form because the removal of individual panels from the space below a freshly poured concrete roof or ceiling must be preceded by a lowering or removal of grooved heads. If the heads are merely lowered, they must descend to a level such that the corresponding panel is located below the neighboring panels while its ribs are withdrawn from the grooves of the corresponding heads. It is then further necessary to provide room for removal of the lowered panel by moving such panel sideways, an operation which is quite complex because the neighboring panels continue to rest on the heads of their props (at least during removal of the first panel or panels of the form). This is the reason that the just described conventional forms failed to gain widespread acceptance in the industry. Instead, builders often resort to modified forms whose props carry connectors adapted to be separably connected with the panels. More specifically, the heads of the props support carriers which can be separably coupled with the panels thereabove.
The modified forms also exhibit numerous drawbacks. Thus, four props with corresponding heads and carriers must be installed below each junction of the corners of four neighboring panels so that the positions of the props must be selected with a reasonably high or very high degree of precision. This necessitates resort to skilled labor for work which should be carried out by unskilled or semiskilled workers. Relatively high degree of accuracy is necessary even if each prop supports two or even as many as four holders.
Moreover, many construction sites are configurated, located and/or dimensioned in such a way that the utilization or installation of conventional forms encounters additional problems. For example, it is often necessary to form a concrete roof between and above erected side walls which surround a cavity or hole in the ground so that one cannot resort to the aforementioned props which must rest on the ground, on a floor or an analogous base. The number of carriers which must be used in the aforediscussed modified forms is rather large, i.e., it invariably exceeds the number of panels. This contributes to initial and maintenance cost of the form.